fix(keyboard): stabilize Flow startup under memory pressure

Delay competing Rime work, add extension memory telemetry and stress coverage, and refresh the 1.8 release assets and metadata for build 79.

OSGKeyboardExt/BootProbe.m

@@ -7,9 +7,30 @@
 // dyld (usually host coexistence or an oversized Shared+Rime mapping).
 
 #import <Foundation/Foundation.h>
+#include <mach/mach.h>
+#include <mach/task_info.h>
 #include <unistd.h>
 
+static double OSGKeyboardExtPhysFootprintMB(void) {
+    task_vm_info_data_t info = {0};
+    mach_msg_type_number_t count = TASK_VM_INFO_COUNT;
+    kern_return_t result = task_info(
+        mach_task_self(),
+        TASK_VM_INFO,
+        (task_info_t)&info,
+        &count
+    );
+    if (result != KERN_SUCCESS) {
+        return -1;
+    }
+    return (double)info.phys_footprint / 1048576.0;
+}
+
 __attribute__((constructor))
 static void OSGKeyboardExtBootProbe(void) {
-    NSLog(@"[OSGDiag/boot] dyld.constructor pid=%d", getpid());
+    NSLog(
+        @"[OSGDiag/boot] dyld.constructor pid=%d foot=%.1fMB",
+        getpid(),
+        OSGKeyboardExtPhysFootprintMB()
+    );
 }